Dual SIM Mobile Phones – Types, Advantages, Drawbacks

Dual SIM phones are highly popular among cell phone users these days. Their ability to allow communication through two different networks/numbers is highly functional. Especially for employees/sales people, who maintain two different numbers for family and professional contacts these dual SIM phones are greatly useful. Further, they also come in handy in case of emergencies, when any one of the SIMs is non-functional (due to no signals) or is out of account balance.

Dual SIM mobile phone: Dual SIM mobile is one which can hold two different SIM cards in the same handset.

Depending on the handset model the SIM cards are accommodated differently in different models. Thus, in some phones both the SIM card slots reside in the battery compartment, behind the battery and in some others one slot is under the battery and the other is outside the phone, just like an external memory card slot.

Types of Dual SIM Mobile phones

Based on the function of the dual SIM phones, they are broadly classified into three types.

Dual SIM shift

Dual SIM active and

Dual SIM standby

Let us know about them in detail:

Dual SIM shift phone: Also known as ‘dual switch dual SIM phones’. These are the basic model of dual SIM phones. The user can insert both the SIMs in the Dual SIM shift phone, but can use only one SIM at a time. While using one SIM, the other remains inactive and thus will be in switched off mode. However, the handset offers flexibility to use both the SIMs alternatively by pressing a specific button on the keypad. Using that key the user can switch between both the SIMs but he can receive calls only to the SIM which is active (in use).

Dual SIM active phone: Dual SIM active phones allow both the SIMs to be active simultaneously. These handsets have two built-in transceivers one of which may support 2G and the another may support 2G/3G. As they have two transceivers, the calls to both the SIMs can be received simultaneously.

When the user is on call on SIM 1 and if receives call on SIM 2, SIM 2 call will be shown as call waiting. He can either lift the call by placing the current call on hold or can hold the call until he finishes his first call. One major drawback of active phones is that since both the SIMs are active, and there are two transceivers the battery life will be reduced typically by about one third when both the SIMs are in use.

Dual SIM Dual standby (DSDS): These DSDS phones also allow both the SIMs to be active at any time, but the only difference is that they have only one transceiver. Though the use of single transceiver helps in improving the battery performance, calls on both the SIMs cannot be received simultaneously. That means, if the user is on a call from SIM 1, at that time if somebody tries to call his SIM 2 number, the caller can only hear the unreachable voice, until he discontinues the call from SIM 1. The user will also not be able to trace the call from SIM 2, as SIM 2 is inactive while he is on call from SIM 1.

Advantages of Dual SIM phones:

Dual SIM phones avoid the need of carrying two different handsets, as the same phone can accommodate both the SIMs.

Some mobile phones accommodate a combination of GSM and CDMA SIM cards. This is quite useful for the people who have separate phones for CDMA and GSM SIMs.

Drawbacks

Poor battery life: Dual SIM phones work on two different transceivers like Dual active phones, need more battery compared to phones with single transceiver. Though many companies are trying to come up with handsets that have better battery life, many existing models have an issue of poor battery life.

Network issues: If two SIMs are of two different networks there is chance that the signal from one may interfere with the other resulting in poor signal strength. Poor signal strength may result in lack of call/voice quality and clarity.

Double radiation strength: This could be the case with active phones, as they allow the user to receive both calls simultaneously. When an user gets calls on both the SIMs, the radiation doubles increasing the risks associated with it.

Though there are many good models that are coming up with dual SIM technologies, as a buyer consider only those models and features which suit your need. Also, do not get carried away by the high price or special features (unless you need them), and give quality and usability of the model the highest priority while buying.

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